The tegumental ultrastructure of juvenile and adult Himasthla alincia (Digenea: Echinostomatidae) was observed by scanning electron microscopy. One-, 5- (juveniles) and 20-day-old worms (adults) were harvested from chicks experimentally fed metacercariae from a bivalve, Mactra veneriformis. The juvenile worms were elongated and curved ventrally. The head crown bore 31 collar spines, arranged in a single row. The lip of the oral sucker had 12 paired, and 3 single type I sensory papillae, and the ventral sucker had about 25 type II sensory papillae. The anterolateral surface between the two suckers was densely packed with tegumental spines with 4-7 pointed tips. The adult worms were more elongated and filamentous, and had severe transverse folds over the whole body surface. On the head crown and two suckers, type I and II sensory papillae were more densely distributed than in the juvenile worms. Retractile brush-like spines, with 8-10 digits, were seen on the anterolateral surface, whereas claw-shaped spines, with 2-5 digits, were sparsely distributed posteriorly to the ventral sucker. The cirrus characteristically protruded out, and was armed with small spines distally. The surface ultrastructure of H. alincia was shown to be unique among echinostomes, especially in the digitation of its tegumental spines, the distribution of sensory papillae and by severe folds of the tegument.
Aging ; Animals ; Integumentary System/*anatomy & histology ; Sense Organs/anatomy & histology/ultrastructure ; Trematoda/*anatomy & histology/*ultrastructure

The aim of this study was to determine the presence and prevalence of larval stages of Dicrocoelium dendriticum and Brachylaima sp. in the first intermediate host, a species of land snail, Helix aspersa, in Turkey. A total of 211 snails were collected in April-May 2014 from pastures in Mersin District. Larval stages of D. dendriticum were identified under a light microscope. Hepatopancreas from naturally infected H. aspersa snails were examined histologically. The prevalence of larval stages of D. dendriticum and Brachylaima sp. in H. aspersa snails was found to be 2.4% and 1.9%, respectively, in Mersin, Turkey. Cercariae were not matured in sporocysts at the beginning of April; however, it was observed that cercariae matured and started to leave sporocysts by early-May. Thus, it was concluded that H. aspersa acts as an intermediate host to D. dendriticumin and Brachylaima sp. in Mersin, Turkey. A digenean trematode Brachylaima sp. was seen for the first time in Turkey.
Animals ; Hepatopancreas/*parasitology ; Larva/anatomy & histology ; Microscopy ; Snails/*parasitology ; Trematoda/anatomy & histology/classification/*isolation & purification ; Turkey

Microphallus species occur primarily as intestinal parasites of birds and mammals, and metacercariae of a new species belonging to this genus have been discovered from the crab, Macrophthalmus dilatatus, in the Republic of Korea. The metacercaria of this fluke was round with 2 thick walls, and the excysted one had mature genital organs. The adult flukes recovered from experimentally infected chicks had numerous intrauterine eggs, well-developed pars prostatica, widely bifurcating ceca, and prominent uterine bulge. After observing internal structures, it was concluded that this species is different from any other known Microphallus spp. Based on the morphology of metacercariae and adult flukes, we describe this specimen as a new species, Microphallus koreana n. sp.
Animals ; Brachyura/*parasitology ; Chickens ; Rats ; Trematoda/*anatomy & histology/*classification/isolation & purification ; Trematode Infections/parasitology/transmission

Maritrema spp. (Digenea: Microphallidae) are parasites of birds, but have not been found in the Republic of Korea. In this study, metacercariae of Maritrema sp. were discovered in the Asian shore crab, Hemigrapsus sanguineus, caught in the mud-flats of Jebu-do, Hwasung-gun, Gyeonggi-do, and the adult flukes were confirmed by experimental infection into mice. Based on the symmetric ribbon-like vitellarium, adult flukes of Maritrema sp. were identified, but did not belong to previously described species in terms of the following morphologic characteristics: ceca reaching to the lateral wall at the anterior border of the ovary; ventral sucker larger than oral sucker; a prominent metraterm; and vitellarium forming a complete ring. Hence, we named this microphallid M. jebuensis n. sp. after the island where the second intermediate hosts were collected. From this study, it has been shown that Maritrema sp. is distributed in Korea and transmitted by the Asian shore crab, H. sanguineus.
Animals ; Brachyura/*parasitology ; Disease Models, Animal ; Metacercariae/anatomy & histology/isolation & purification ; Mice ; Mice, Inbred ICR ; Republic of Korea ; Trematoda/anatomy & histology/*classification/*isolation & purification ; Trematode Infections/parasitology/pathology

The prevalence of fish-borne trematodes (FBT), including Clonorchis sinensis, is still high in riverside areas of the Republic of Korea. The author reviewed the detection and identification methods, differential keys, fish intermediate hosts, and morphological characteristics of FBT metacercariae. FBT metacercariae found in freshwater fish are classified mainly into 4 families, i.e., Opisthorchiidae, Heterophyidae, Echinostomatidae, and Clinostomidae. The metacercariae of C. sinensis, found in 40 species of freshwater fish, are elliptical and 0.15-0.17 x 0.13-0.15 mm in size, have nearly equal sized oral and ventral suckers, brownish pigment granules, and an O-shaped excretory bladder. Their general morphologies are similar to those of Metorchis orientalis (except in the thickness of the cyst wall). Metagonimus spp. (M. yokogawai, M. takahashii, and M. miyatai) metacercariae are subglobular or disc-shaped, and 0.14-0.16 mm in diameter. They have yellow-brownish pigment granules, a ventral sucker deflectively located from median, and a V-shaped excretory bladder. The metacercariae and fish intermediate hosts of Centrocestus armatus, Clinostomum complanatum, and 3 echinostomatid flukes (Echinostoma hortense, E. cinetorchis, and Echinochasmus japonicus) were summarized. FBT metacercariae detected in brackish water fish are mainly members of the Heterophyidae. The morphological characters, identification keys, and fish intermediate hosts of 7 species (Heterophyes nocens, Heterophyopsis continua, Pygidiopsis summa, Stellantchasmus falcatus, Stictodora fuscata, Stictodora lari, and Acanthotrema felis) were also reviewed. The contents treated in this study will provide assistance at the laboratory bench level to those working on recovery of metacercariae from fish hosts and identifying them.
Animals ; Fishes/anatomy & histology/*parasitology ; Fresh Water/parasitology ; Host-Parasite Interactions ; Humans ; Republic of Korea ; Trematoda/anatomy & histology/classification/*isolation & purification ; Trematode Infections/*parasitology ; Zoonoses/*parasitology

Migratory birds have been suspected as playing a central role in transmission of various trematodes, but few surveys have been undertaken in the Republic of Korea. In the present study, we describe new fauna of microphallid flukes in Korea. Two species of microphallids were found in the intestines of 2 migratory bird species, namely the red necked stints (Calidris ruficollis) and the terek sandpiper (Xenus cinereus), in a coastal area of Gunsan-si, Jeollabuk-do. The microphallids recovered from the latter were 451 microm in length and 217 microm in width, and the eggs were very small, 13 microm by 8 microm. They had the characteristic extracecal vitellaria intruding into the median posttesticular area, belonging to Endocotyle incana. Another microphallids were discovered from both migratory birds, 417 microm in length and 249 microm in width. The cirrus was projecting into the genital atrium in form of male papilla, and bounded by a muscular flap, termed pseudogonotyl. They were identified as Spelotrema pseudogonotyla in consideration of the distinctive male papilla and pseudogonotyl. Besides these flukes, Maritrema obstipum and Gynaecotyla squatarolae also were recovered. This paper is in fact the first report on the presence of Spelotrema and Endocotyle in Korea.
Animals ; Bird Diseases/*parasitology ; Charadriiformes/*parasitology ; Microscopy ; Republic of Korea ; Trematoda/anatomy & histology/*classification/*isolation & purification ; Trematode Infections/parasitology/*veterinary ; Zygote

Gynaecotyla squatarolae (Digenea: Microphallidae) adult flukes were recovered from experimental chicks at day 4-6 post-infection and their tegumental ultrastructure was observed with a scanning electron microscopy. They were pyriform in shape, and their anterior halves were concaved ventrally. The whole body surface was covered with tegumental spines, which were wide and 16-17 digitated between oral and ventral suckers. The density of spines and number of digits decreased posteriorly. The oral sucker was subterminal and the excretory pore was at the posterior end of the worm. wo ventral suckers were similar in appearance and protruded near midline of the worm. The genital atrium was dextral to the small ventral sucker. The dorsal surface was covered with tegumental spines, but the spines were sparser than on the ventral surface. On the middle portion of the dorsal surface, a small opening presumed to be the Laurer's canal was een. From these findings, it has been confirmed that the adult G. squatarolae has unique characteristics in the surface ltrastructure.
Animals ; Brachyura/*parasitology ; Chickens ; Microscopy, Electron, Scanning ; Trematoda/anatomy & histology/classification/*isolation & purification/*ultrastructure ; Trematode Infections/*parasitology

Adult worms of Parvatrema spp. (Digenea: Gymnophallidae) were found in the intestines of 2 species of migratory birds, i.e., a great knot, Calidris tenuirostris, and 2 Mongolian plovers, Charadrius mongolus, in the coastal area of Gunsan-si, Jeollabuk-do in October 2009. The recovered Parvatrema worms were 79 in total number and composed of 2 species. The worms from a great knot were 289 micrometer in length with the oral and ventral sucker ratio of 2 : 1. They had a single vitellarium, and their intrauterine eggs were 25.0 x 17.5 micrometer in size. These findings were compatible with P. duboisi (Dollfus, 1923) Bartoli, 1974 (syn. P. timondavidi Bartoli, 1963). The worms recovered from the Mongolian plovers were smaller in length than P. duboisi and had 2 vitellaria. The oral and ventral sucker ratio was 2.5 : 1, and the eggs were 17.5 x 8.8 micrometer in size. These worms were assigned to be P. homoeotecnum James, 1964. This is the first report on the natural final hosts of Parvatrema spp. in Korea.
*Animal Migration ; Animals ; Bird Diseases/*parasitology ; Charadriiformes/*parasitology/physiology ; Trematoda/anatomy & histology/*isolation & purification ; Trematode Infections/parasitology/*veterinary

Parvatrema chaii n. sp. (Digenea: Gymnophallidae) is described using the worms recovered from experimentally infected mice in Korea. The metacercariae were collected from surf-clams, Mactra veneriformis, from a tidal flat in Sochon-gun, Chungchongnam-do. The metacercariae were elliptical (0.262 x 0.132 mm), and the genital pore had an anterior arch of 16-17 sensory papillae in scanning electron microscopic view. Adult worms were ovoid to foliate (0.275-0.303 by 0.140-0.150 mm), and their characteristic features included the presence of lateral lips, short esophagus, genital pore located some distance anterior to the ventral sucker, club-shaped seminal vesicle, a compact to slightly lobed vitellarium, elliptical eggs (0.018-0.020 by 0.010-0.013 mm), and absence of the ventral pit. This gymnophallid is classified as a member of the genus Parvatrema because of the location of the wide genital pore some distance from the ventral sucker, and the absence of the ventral pit. It differs from previously reported Parvatrema species, including the type species, P. borinquenae. In particular, the morphologies of the vitellarium and the genital pore with an anterior arch of 16-17 sensory papillae are unique features. Therefore, we propose it as a new species, Parvatrema chaii n. sp. (Digenea: Gymnophallidae).
Animals ; Bivalvia/*parasitology ; Disease Models, Animal ; Mice ; Microscopy, Electron, Scanning ; Trematoda/anatomy & histology/*classification/*isolation & purification/ultrastructure ; Trematode Infections/*parasitology

Freshwater fish from Vientiane Municipality and Savannakhet Province, Lao PDR were examined by the muscle compression and artificial digestion methods to know the infection status with trematode metacercariae. In the fish from Savannakhet, 2 species of metacercariae, Opisthorchis viverrini and Haplorchis taichui, were detected. O. viverrini metacercariae were found in 6 species of fish, Puntius brevis, Hampala dispar, Esomus metallicus, Mystacoleucus marginatus, Puntioplites falcifer, and Cyclocheilichthys armatus. H. taichui metacercariae were detected in 3 species of fish, P. brevis, P. falcifer, and M. marginatus. In the fish from Vientiane, 4 species of metacercariae, O. viverrini, H. taichui, Haplorchis yokogawai, and Centrocestus formosanus, were detected. Among them, O. viverrini metacercariae were found in 7 species of fish, Onychostoma elongatum, C. armatus, H. dispar, P. brevis, Cyclocheilichthys repasson, Osteochilus hasseltii, and Hypsibarbus lagleri. The metacercariae of H. taichui were detected in 6 species of fish, C. repasson, O. elongatum, C. armatus, H. dispar, Labiobarbus leptocheila, and Cirrhinus molitorella. The metacercariae of H. yokogawai were found in 9 species of fish, C. repasson, O. elongatum, C. armatus, H. dispar, Labiobarbus leptocheila, O. hasseltii. C. molitorella, Hypsibarbus wetmorei, and H. lagleri. The metacercariae of C. formosanus were detected in 4 species of fish, C. repasson, P. brevis, O. hasseltii, and C. molitorella. From these results, it is confirmed that fishborne trematode metacercariae, i.e. O. viverrini, H. taichui, H. yokogawai and C. formosanus, are prevalent in various species of freshwater fish from Savannakhet Province and Vientiane Municipality, Lao PDR.
Animals ; Fish Diseases/epidemiology/*parasitology ; Fishes ; Fresh Water ; Laos/epidemiology ; Trematoda/anatomy & histology/classification ; Trematode Infections/epidemiology/parasitology/*veterinary